1. Field of the Invention
The invention relates to a method for emptying supply lines for supplying coating applying devices of a coating unit with coating means such as, for example, paints, from one or a plurality of coating means container(s) or reservoir(s), whereby the supply line has a valve device, which makes it possible that the coating means volume present in the supply line be redirected counter to the direction of flow into a coating means reservoir or a supply line at the time of processing the coating means.
2. Description of the Prior Art
This type of supply line can, for example, be paint ring lines of painting systems but also paint supply lines leading away from the paint ring lines, which are arranged between the ring line and the paint change device.
Particularly when operating painting systems with alternating paints, there has always been the problem that individual components of the painting system must be cleaned prior to a paint change, whereby especially the paint present in the supply lines must be removed. For reasons of environmental protection and costs it is advantageous when doing this, if the paint contained in the supply lines does not have to be discarded but can be redirected back to a paint supply container or to a paint ring line.
The German patent DE-PS 197 09 988, for example, proposes a solution for the cleaning problem of a paint supply line arranged between a paint change device and a paint spray gun, by arranging a displacement body within the supply line and displacing the paint volume present in the supply line by movement of the displacement body against the direction of flow of the paint and out of the supply line and redirecting it into the paint change device or into the paint ring line. Then the supply line is flushed with a solvent in the direction of flow of the paint. The solvent present in the supply line is then pushed by the displacement body, which must be moved back into its starting position anyway, out of the supply line in the direction of flow of the paint. The drawback in this proposed solution is primarily the high control effort for the displacement body movement and the extensive sensor technology for determining the position of the displacement body.
The object of the present invention, starting with the described prior art, is to provide a method for cleaning of a supply line of a coating system such as, for example, a paint ring line or a paint supply line of a painting system, which on the one hand can be realized with the least possible technical input and on the other hand makes it possible to extensively recover the coating means of the coating means volumes or paint volume present in the supply line. Moreover, a further object of the invention is to propose a suitable supply line for this cleaning or emptying method.